Thrust meter



Aug. 1, 1950 H. M. CONWAY, JR

THRUST METER 2 Sheets-Sheet l Filed May 2, 1947 INVENTOR. f/iZCaizzaqyWe ATTCI RN EYB Patented Aug. 1, 1950 UNITED STATES PATENT OFFICE HobartM. Conway, Jr., Atlanta, Ga.

Application May 2, 1947, Serial No. 745,572

2 Claims.

The present invention relates to the general class of measuring andtesting appliances, of the pull measuring. type, and more specificallyto an improved thrust meter which while well adapted for various uses,is especially designed for testing, measuring and indicating the thrustor pull of small power plants, as for instance the engine or motor andpropeller or jet propulsion engines employed in the propulsion of modelairplanes, in order to ascertain and determine the performance oflaboratory work as compared with, actual practice that may lead toadjustments and differences in values.

The primary object of the invention is the provision of a portable,compact, and eificient appliance of precision which is composed of aminimum number of parts that with facility may be manufactured at lowcost of production, and assembled with convenience to provide anappliance upon which the testing power plant may be detachably mountedfor operation and observation.

The. invention consists essentially in. certain novel features ofconstruction and combinations and arrangements of parts for attainingthese results as will hereinafter be described and more specifically setforth in the appended claims.

In the accompanying drawings I have illustrated a complete example of aphysical embodiment of my invention wherein the parts are combined andarranged according to one mode I have devised for the practicalapplication of the principles of the invention. It will however, beunderstood that changes and alterations are contemplated and may be madein these exemplifying drawings and mechanical structures, within thescope of my claims, without departing from the principles of theinvention.

Figure l is a view in front elevation of a testing and meteringappliance in which my invention is embodied, showing a small asolineengine or motor and its propeller detachably mounted thereon.

Figure 2 is a view in elevation of the structures in Fig. 1 disclosingthe motor and propeller in front elevation.

Figure 3 is a vertical sectional View at line 3-3 through the hollowbase, stand, or housing of the appliance and disclosing the actuatingand operating mechanism for the thrust meter.

Figure 4 is a transverse vertical sectional view at line 4-4 of Fig. 3.

Figure 5 is a View similar to 3 showing the actuating and operatingmechanism at the magnitude of a thrust movement.

Figure 6 is a horizontal detail sectional view at line 6-45 of Fig. 5.

Figure? is a. detail fragmentary view showing the rocker shaft or torqueshaft and accessories; and

Figure Bis a detail fragmentary view at the lower end of the thrust armor standard of the appliance on which the power plant is mounted fortesting.

In this preferred form of the invention, in order that the generalarrangement andutility of parts may readily be understood I have illustrated in the assembly drawings a conventional small-power-plant thatmay be a gasoline engine or motor E having the usual shaft S and apropeller P, as employed on model airplanes. For testing, the powerplant is detachably mounted upon the upper end of a thrust arm orstandard I in the nature of an upright flat plate or blade thatterminates at its upper end in a U-shaped cradle or yoke 2 havinglateral attaching flanges 3, and the flanges 4 of the engine housing arerigidly attached, asby bolts 5, tothe yoke flanges for holding theengine to betested for thrust.

The movable thrust arm is supported in and projects above a hollowrectangular base 6, which is provided with attaching flanges F in orderthat the portable appliance may be bolted to a bench, table, or othersupport, and the flat top of the hollow base is slotted, as at 1parallel with the plane of the engine shaft, to permit movement of thethrust arm in accord with power developed by the operating motor orengine carried by the arm or standard I.

The front edge 8 of the standard or upright thrust arm is disposed in aplane perpendicular to the engine shaft while the rear edge 9 divergestoward the lower end of the arm to provide a wide base that is equippedwith a pair of spaced bearing sleeves I0, [0, that are slidably mountedupon a guide bar I I located in a horizontal plane parallel with theengine shaft.

The guide bar is located within the upper portion of the hollow base andrigidly supported in opposed walls of the base by headed ends l2, l2,exterior of the base. By this arrangement of the engine shaft andparallel aligning bar H, together with the perpendicular arm, thepropeller of the testing engine when in operation develops and impartsto the thrust arm a movement longitudinally of the guide bar, whichmovement is instrumental in activating and operating the thrust meterand its indicator.

The thrust and consequent sliding movement of the torque arm or standardon its guide bar,

are transmitted to the meter and indicating mechanism in terms of energyor force.

For this purpose, the torque arm or standard I, or preferably one of itsbearing sleeves Ill, within the hollow base 6 is equipped with aconnecting link 13 pivoted thereto at M and the link is also pivoted at15 to a rock arm 16 rigidly mounted upon a torque shaft I'l disposed ina plane perpendicular to the plane of the guide bar, and located'beneaththe bar where it is journaled in bearings 18 in opposite vertical wallsof the hollow base 6.

A quadrant shaped, segmental, or arcuate gear I9 is rigidly mounted uponthe rock shaft I! to turn therewith, and this gear constantly mesheswith a reduced pinion 2D rigidly mounted on and rotatable with anindicator shaft 2| parallel with and located in the same horizontalplane with the rock shaft or torque shaft.

The indicator shaft is journaled in a bearing 22 integral with an insetor recessed front wall 23 of the hollow base, which forms a'circulardial for the pointer or needle 24 located exterior of the base andmounted on the projecting end of the indicator shaft, for co-operationwith the annular scale on the dial that displays in units of energy thetorque or thrust developed by the engine and its propeller.

For initially setting the metering mechanism at zero on the dial, a setscrew 26 is mounted in a hollow bracket 21 mounted on top of the base 6,and provided with a non-rotatable coupling head 28 that projects througha hole in the top wall of the hollow base. A helical spring 29 isconnected at its upper end to the coupling head 28, and its lower end isanchored at 313 to the segmental gear 19 at a point between the rockshaft and the indicator shaft and below the planes of these shafts, inorder that the screw may be turned to swing the gear and rotate thepinion for setting the meter. The spring ofiers resilient resistance tothe forward turn of the rock shaft, and also automatically retracts themechanism to zero position at the cessation of applied thrust.

Having thus fully described my invention, what I claim as new and desireto secure by Letters Patent is:

1. In an apparatus for measuring and indicating the thrust of a powerplant, the combination comprising a hollow base having a horizontalguide bar, a movable standard slidable on the bar, means for maintainingsaid standard in upright position, means for operatively mounting apower plant upon the standard whereby thrust is transmitted from thepower plant to the standard, a transversely arranged rock shaft in saidbase, a rock arm on said rock shaft, a link pivotally connecting saidrock arm and standard, a segmental gear fixed to said rock shaft, anindicator shaft and an indicator thereon, a pinion on the indicatorshaft coacting with said gear, and spring means for resisting the thrustdeveloped by the power plant.

2. In an apparatus for measuring and indicating the thrust of a powerplant, the combination comprising a hollow base having a horizontalguide bar, a movable standard slidable on the bar, means for maintainingsaid standard in upright position, means for operatively mounting apower plant upon the standard whereby thrust is transmitted from thepower plant to the standard, a rock shaft in said base, a rock arm onsaid rock shaft, means pivotally connecting said rock arm and standard,a segmental gear fixed to said rock shaft, an indicator shaft and anindicator thereon, a inion on the indicator shaft coacting with saidgear, and resilient means for resisting the thrust developed by thepower plant.

HOBART M. CONWAY, JR.

REFERENCES CITED FOREIGN PATENTS Country Date Great Britain Apr. 8, 1919Number

